The present invention relates to the field of reciprocating internal combustion engines. More specifically, the invention relates to intake and exhaust valves and their relationship to the angle, position and shape of the valve head. The intake valve cooperates with the intake port of an induction system of the engine whereby it is operative to control the direction of the admission of an induction charge into the combustion chamber of the engine so as to create a highly efficient flow of the production charge into and within the combustion chamber. This allows for a more efficient and straight intake port and more efficient combustion chamber. The exhaust valve cooperates with the exhaust port of an exhaust system associated with the engine to control the exit of exhaust gases from the combustion chamber into the exhaust system so as to create a more efficient exhaust port and more efficient combustion chamber.
In the field of internal combustion engines, many improvements to intake and exhaust valves have been made. For example, U.S. Pat. No. 4,779,584, to Warren Mosiler discloses an intake valve having an aerodynamic design in the flow path subsequent to the valve seat portion of the valve. Others have provided fins or ribs on the upstream side of the valve head, such as that shown in U.S. Pat. No. 3,090,370, to H. W. Kimball and U.S. Pat. No. 4,309,969, to William R. Matthes, to increase the turbulence of the intake charge and swirl and to increase combustion and port flow efficiency. But the fins and ribs are cumbersome, complex to manufacture, and restrict air flow efficiency into the combustion chamber. Additionally, the fins or ribs do not address the necessity for a substantial bend in the intake and exhaust ports to allow room for valve stem guides, valve spring seats, and related parts. In U.S. Pat. No. 5,081,965, to Craig E. Walters et al., the invention has a region of the upper head portion with runout, but both the head region and the stem region have a common axis. Here, the valve stem is straight and located in the center of the valve head. The centerline of the valve stem is perpendicular to the face of the valve head, and the valve head is round or cylinder-shaped when looking down the valve stem centerline toward the valve head. In actual practice, this design limits the design of the intake and exhaust ports, the location of the valve springs and other valve activating mechanisms such a rocker arms, push rods and camshafts. The valve actuating mechanisms are more compact and of a more simple design if the valve stems are in a straight line and/or parallel to each other instead of angled in different directions. This is not an ideal arrangement for the combustion chamber. This is also not an ideal arrangement for the location and shape of the intake and exhaust ports and valves within the combustion chamber. Also, intake ports often have to be shaped with bends to go around pushrods coming from the camshaft to the rocker arms. This is an important limitation of the prior art since compactness of valve actuating mechanism is desired. Thus, it is often the case that intake and exhaust ports are designed with relatively sharp angular bends connecting a throat portion near the valve seat with an exit or entrance portion extending laterally out through the side wall of the port defining cylinder head or engine block.
It would be desirable to provide an improved intake and exhaust valve which significantly reduces the resistance in the flow of the intake charge and increases the efficiency and effective flow of the intake charge into and within the combustion chamber. It would also be desirable to improve the shape of intake port, combustion chamber and corresponding valve seat, thereby improving the efficiency of the combustion process. Also, it would be desirable to provide an exhaust valve that significantly reduces the resistance of the exhaust flow out of the cylinder and engine thereby improving the efficiency of the combustion process.
In a hemispherical type combustion chamber, or in combustion chamber types where the faces of the valve heads are not on the same plane but at angles to each other, such as generally facing one another, the tops of the valves are spread apart at an angle, thus making the top of the cylinder head wider, larger and heavier and making the head more difficult to design the valve actuating mechanisms. It would be desirable to provide the valve faces to have angles relative to each other, but where the valve stems can be more parallel to each other than is possible with prior art valves, thus simplifying valve actuating mechanisms and allowing more compact and lighter cylinder heads and overall smaller engine size.
In a typical engine, the combustion chamber available area is round like the top of the piston and cylinder. The use of valves with round heads wastes space and is a poor usage of valuable combustion chamber volume. Therefore, it would be desirable to have a valve head shape that more effectively and efficiently uses available combustion chamber volume and that also adds swirl and turbulence to intake charge, thereby improving the quality of the intake charge into the combustion chamber.
The embodiments of the present invention allow a substantial increase in the efficiency of the airflow and shape of the intake port, valve seat and combustion chamber of an engine, to increase the overall efficiency of the engine and decrease pollution caused by the engine. By increasing the efficiency of the intake and exhaust systems, the present invention will increase engine power and torque, increase gas mileage and B.S.F.C., thereby decreasing engine pollution.
The embodiments of the present invention would work equally well on engines with multiple intake and or multiple exhaust valves per cylinder. Also, the embodiments of the present invention would work equality well on engines that use gas, diesel, alcohol, natural gas and others fuels, and either two or four stroke type engines. The embodiments of the present invention allow convenient integration with other conventional engine systems, such as ignition systems, cylinder heads, carburetor and fuel injection systems, exhaust and intake systems, and pollution control systems.
The present invention is directed to an intake and exhaust valve and valve guide for an internal combustion engine. The valve has a valve head for mating with a valve seat and the valve has a stem having a stem end and a head end. The stem is sized to slidably move in the valve guide within the engine and the head for being moved between open and closed positions as the stem is moved in the guide.
In one preferred embodiment, the valve head has a center point, and the valve stem longitudinal axis is substantially offset from the center point of the valve head. Preferably, the valve head is attached to the valve stem at a point from between about 20 percent to about 30 percent of the diameter of the valve head, as measured from a perimeter of the valve head.
In another preferred embodiment, the valve has a valve stem having a longitudinal axis and the valve head has an end having a generally planar surface. Here, the longitudinal axis and the planar surface are at an angle other than perpendicular to one another. Preferably, the planar surface is oriented at approximately 24 degrees to 30 degrees from the longitudinal axis.
In another preferred embodiment, the valve head has an irregular perimeter. The perimeter has a generally straight edge, radiused corners adjacent the straight edge, and another edge being rounded and generally smoothly radiused to the straight edge.
In another preferred embodiment, the valve head has a stepped, non-planar shape with respect to the plane of the face of the valve head.
In another preferred embodiment, the valve head has a shape that is generally pie-shaped having radiused comers. Preferably, the pie-shape is approximately a one-fourth section of a pie.
Finally, in another preferred embodiment, the valve stem longitudinal axis is substantially offset from the center point of the valve head, and the valve head has an end having a generally planar surface, wherein the longitudinal axis and the planar surface are at an angle other than perpendicular to one another.
In all the preferred embodiments, an anti-rotation mechanism to prevent rotation of the valve may be included.